Cutter chain



.Fuly 1 1924. 3,499,944;

T. E. FRAY VCUTTER CHAIN Filed June 16. 1925 Patented July i, 1924.

unirse STATES inane PATENT OFFICE.

COMPANY, or' CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS.

GUTTER, cHAIN.

Application ined June 16, 1923. serial no. s453653.

To @ZZ when@ t may confiera:

Be it known that I, TH'oMAs E. PRAY, a citizen of the United States, resida@ at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Cutterv Chains, of which the following' is a specification.

This invention relates to improvements in cutter Chains for mining machines and has for its principal Object to provide a simple and durable construction of chain block and cutter bit. j

More specifically, the object of my invention is to provide an improved construction and arrangement of clamping means for the cutter bit in a block of the type disclosed in my prior applications' bearing Serial number 431,250, filed Deeember ie, i920, and Number 600,499, vfiled November 13, 1922, with particular Vrefere`n ':e to the clamp-- ing device for the bit.

The inventionA may be best understood by reference to the accompanying drawings in which: Y v

Figure `1 is a side view of a chain block with the bit in place.

Figure 2 is an end view of the chain showing it in position in a cutter head of a mining machine.

Figure 3 is a perspective view of an improved bit gripping element forming a part of my invention.

Figure 4 is a detail view of the clamping element for the bit with a portion thereof broken away.

In the drawings I have shown a cutter chain for mining machines which is made up of a series of chain blocks 1, 1, pivotally connected together by a series of suitable straps 2, 2. The chain in use is an endless chain that passes about a driving sprocket and works in a grooved cutter head 7 The cutter head is preferably provided at the top and bottom with guideways 3, 3, in which the restraining lips 4 and 5 on the blocks and straps are retained. The blocks are provided with cutter bits 6, 6'. The cutter cha-in is made up of a series of such chain blocks which extend at various angles from the grooved cutter head, as shown in Figure 2.

The cutter bit 6 is preferably of flat bar stock having a substantially uniform crosssection intermediate its ends and is inclined forwardly and outwardly in a bit receiving aperture 9, formed in the body of the block.

Means for securing the bit in the block comprise a clamping member 14 which fits in an aperture 15 extending lengthwise through the outer portion of the block at substantially right angles to the bit 6. This aperture is preferably made of substantially uniform cross-section throughout. its length, as for example, it may be a drilled hole in which the clamping member 14 is fitted. In the' form shown in the drawings, the forward end of the clamping member 14 is adapted to extend through and be substantially iiush with the forward face 8 of the bloclr` as is disclosed in my co-pending application bearing Serial Number 600,499, although present invention does not relate to this feature, and the clamping member 14 may also stop short of the forward face 8 ofthe block, as in the form disclosed in another CO-pending application bearing Serial Number 431,250.

The specific feature of novelty forming the' subject matter of the present invention relates to the provision of a gripping device to be used in conjunction with a clamping member 14 so as to securely hold the bit 6 in place in the block. One of the difficulties in the operation of cutter chains having removable bits therein is that of securing the bits in the blocks so that they cannot work loose while in operation. The clamping pressures which may be exerted by screw devices of the ordinary kinds have not been satisfactory for this purpose where the engaging vsurface of the clamping device is a plane surface. It therefore has been found necessary in devices of thischaracter to provide a gripping device, preferably of relatively hard material, such as tool steel, having roughened surfaces adapted to a'ord a firm grip upon the bit. In the present invention I provide an improved form of gripping device comprising a plug 20. This plug is preferably formed of cylindrical stock with an enlarged head 21 at one end thereof. In order to provide a firm gripping contactwith the bit one side of the plug is machined or cut away to form a plurality of toothed projections 22, 22 throughout the length of the plug, as shown in Figure 3. The plug is fitted in a suitable aperture adjacent the bit receiving aperture 16 formed in the clamping member in alignment with the bit receiving aperture 9 of the block, the arrangement being such that the E. PRAY, or CICAGO, ILLINOIS, AssIe-Nola 'ro eoonrean MANUFACTURING toothedprojections 22 Will engage the bit when the clamping lmember is inthe position shown in Figure l.

`The head 2.1 of the plug 2O is preferably arranged on themside of the clamping mem-` ber nearest' the 'cutting end of the bit tol withstand the endWise thrust of theI `bit While in operation. By reason of this arrangement, the plug 20maintainsits position Without the use of special securing means and yet may'ibe readily removedior replacementl wheny it becomes Worn. 5

The-'rear end ofthe clamping/member is provided With a'threaded portion 18 adapt'- ed to eXtend'beyond the rear aceoffthe block and having a nut'l9 thereon.-v Means are provided for.' preventing tvliev'rotation of the clamping member, such as a fpin 23 extending throughv the blockfand'engagin'g al flattened surface T24 orm'ed'on ythe-clamping member. The pin v.25 isalso adapted to engage a shoulder 25 on 'the clamping member t0 retainthe latter in the block. Infthe improved form* herein disclosed :it Will be seen that the gripping" device 'isof' simple construction, readily 'fixed liny yplace in the clampingdeviceand provides a firm' grip Vupon the cutter bit throughout thev lengthand Widthhof' the grippingy surface of the plug. The 'plug When Worn Amay be readily removed for replacementf -f Igclaimas'fmy invention:` #1.; Incombination with 'a cutter chain block'for mining=machines-having a` bit re-Y ceiving aperture therein, a bit,-aclamping membervarranged transversely of said bit receiving vaperture and having means ad- Yijustable from the rear end of said block Jfor dra-Wing Said Clamping member rearwardly A tov secureV `the bit in bearing lengagement in said bit receiving aperture," and a bit grip- .pingdevice comprising a plug formed of vcylindrical stock, said plug being seated transversely-in said clamping member and provided With a plurality of toothed projections formed along one sider thereof 'iii position' to engage the bit.Vlr

In' combination WithV a: cutter Ychain block for mining machines :having a forwardly inclined bit receiving aperture there; in,'a'bit; a clamping member -arranged trans-Y versely of said'bit receiving apert-ure'and having means adjustable from the Vrear Vend of 'said block' for ldrawing* said clamping member rearwardly Vto secure' the bit in bearing engagement in said bit receiving aperture, a bit gripping device comprising a plug formed of cylindrical stock,said plug being seated transversely in 'saidclamping member and' provided' With a plurality fof toothed projections formed along f one side thereof ini-position to engage the'bit, Vand a head on said bit gripping member arranged' at Ythe outer side of said clampingmember: inV position to .WithstandendWise thrustjof the bit While in operation. I' Y Si nedat Chicago, inthe countyv of Cook and tateof Illinoisthisllth'day of'Jhune,`

1923. THOMAS E. PRAY? 

